Method of spinning filamentary strands



April 9, 1957 G. M. ALLEN METHOD OF SPINNING FILAMENTARY STRANDS FiledJune 2, 1952 INVENTOR.

" GEORGE M. ALLEN AT) Er United States Patent METHOD OF SPINNINGFILAMENTARY STRANDS George M. Allen, Swarthmore, Pa., assiguor toAmerican Viscose Corporation, Philadelphia, Pa., a corporation ofDelaware Application June 2, 1952, Serial No. 291,185

1 Claim. (Cl. 18-54) This invention relates to method of spinningstrands of filamentary material in the presence of liquid materialsapplied thereto to harden or set the filament-forming substance. Themethod is particularly applicable to the spinning of viscose rayonyarns, and for purposes of illustration, the invention is described withrespect thereto.

In conventional spinning processes involving the step of spinning afilament-forming material into a bath of liquid coagulant, spinning isordinarily conducted in such amanner as to cause contamination of thespinning bath by the products of reaction and the dilution of the bathby Water, formed also as a product in the reaction of the coagulant withthe filament-forming material. Such contamination or the dilution of thespinning bath necessitates the recirculation in large quantities of thebath liquid and the introduction of large amounts of concentratedcoagulant solution to maintain the concentration of the bath at a levelsatisfactory for proper coagulation. Moreover, the products of reactionwhich contaminate the bath reduce the efliciency of the coagulationtreatment.

It isan object of the invention, therefore, to provide, spinning methodwhereby a liquid coagulating material is brought into contact with astrand-forming material immediately after extrusion and is preventedfrom re turning to the supply source to avoid dilution andcontamiriation thereof, and to eflect a more efficient use of thecoagulant itself. It is another object to provide a method forwet-spinning a multifilament strand by which the material of the strandmay be subjected, in rapid sequence, to an initial coagulation treatmentand a sub sequent regenerating treatment prior to a stretchingtreatment. Still another object is to provide a method for preventingcontamination and dilution of a spinningba'th while applying varioustreatments to the filament -forming material, regardless of whether thefilament-forming material is extruded into a stationary bath ofcoagulent' or into a tube conducting a concurrent stream of liquidcoagulant. A further object is to provide a method in which a godet isemployed for abstracting liquid from a liquid-laden strand passingupwardly onto the godet, and discharging the liquid from a po'intspacedfurther along the periphery of the godet to prevent run-back along thesection of strand approaching the godet. Still another object is toprovide a method in which a snubbing systemcomprising godets is utilizedfor handling. a section of strand which is passing through the earlystages of conversion from a filament-forming material into filaments ofsubstantial tensile strength. Other objects, features and advantageswill become obvious from the following description of the invention andthe drawing relating thereto in which Fig. l is a diagrammatic view ofapparatus for processing a liquid filament-forming material into strandpackages, with portions ofthe structure shown in section; Fig. 2illustrates a godet system used in the apparatus of Fig. l with portionsof the structure shown in section;

Patented Apr. 9, 1957 Fig. 3 is a diagrammatic view of a modifiedconstruction of a portion of the apparatus illustrated in Fig. 1;

Fig. 4 illustrates, partly in section, a portion of the apparatusshownin Fig. 3;

Fig. 5 is a vertical section taken approximately along a plane normal tothe axis of a godet, such as used in the apparatus of Fig. 1;

Fig. 6 illustrates a modified apparatus for handling a running strand;

' Fig. 7 illustrates another modified apparatus for handling a runningstrand; and

Fig. 8 is a modification of a portion of the apparatus illustrated inFigs. 1 and 3.

in brief, the present invention relates to a method of passing afreshly-spun liquid-laden strand through a godet system which comprisesone or more godets, and discharging the strand, with the filamentarymaterial thereof in a substantially converted or regenerated condition,toward a takeup means operating at a linear speed greater than theperipheral speed of the godets. The

godets preferably comprise annular transversely-toothed surfaces orserrated portions and smooth surfaces so that the strand, after beingexposed to a liquidcoagulant, may be first supported on the brokensurface of a toothed section with very little tension and while in arelatively plastic state, and then on the smooth section. The smoothsections are more satisfactory for snubbing the strand since tension maybe applied by the take-up means without damaging the strand, and forother reasons explained hereinafter. When the strand passes in an upwarddirection from a liquid coagulant, the liquid carried by the strand israpidly separated therefrom by godet having teeth, the forward surfacesof which are canted forwardly in the direction of rotation. The axis ofone godet is preferably canted with respect to the axis of the other sothat the strand may be advanced lengthwise thereof.

in one method of the invention, the lower godet is canted downwardly sothat the smooth portion thereof may be run partly immersed in a bath ofliquid, heated sufficiently to accelerate the regeneration of thecellulosic material comprising the strand. The application of a heatedregenerating liquid may be suppiemented by addi, tional duct meansmounted for discharging the liquid onto the smooth sections of thegodets, or by means for conducting some of the liquid lengthwise of aportion or" the path of the strand as it passes from the godets to thetake-up means.

Fig. l is a diagrammatic illustration of apparatus for spinning a yarnof artificial filaments in accordance with one method of the invention.A spinneret is supported in a tank 6 having overflow means, such as tube7, for maintaining a liquid coagulant at a predetermined level 8. Afilament-forming material is extruded from the spinneret into the bathin the form of fine streams that are con verted by the coagulant intofilaments comprising the strand 9. The strand passes upwardly onto theserrated portion or toothed-surface of a godet it) having teeth 11 whichare canted forwardly in the direction of its rotation as shown in 2. Oneor more windings of the strand 9 are supported around the godet 1G andanether godet 12, having one port-ion of its peripheral surface smoothand another portion fluted. The godets are connected in driverelationship by an arrangement, such as the sprocket and chain system 13shown, whereby they may be driven by a 3 formed betweentheteeth.Conversely stated, the leading surfaces of the teeth or flutes 11 extendradially inwardly froui the outer diameter of the fluted section ofgodet and backwardly with respect to the direction of rotation of thegodet.

The godet 12 may be provided with teeth or serrated portion similar tothose of godet lit Advancement of the thread in a direction lengthwiseof the godets may be accomplished by guides, or the godets may besupported as shown with their axes canted with respect to each other.One important function of the godets 1t and 12 is to separate a liquidcarried from the tank 6 by the strand, so that it may be collected in ahood 14, which surrounds the godets, and is thereby prevented fromreturning to the tank 6. As the process and apparatus being described ishighly adaptable to the making of large denier yarns such as used intire construct-ion, the yarns, immediately after formation near thespinneret face, are relatively thick, plastic and incompletelycoagulated, and are capable of carrying substantial quantities of liquidfrom the tank 6 upwardly toward the godet It. Apertures are provided forthe yarn through the hood 14, one (13a) along the path of the yarn as itpasses from the bath to the godet '10, and the other (1311) along thatportion of path extending from the godet 10 toward a trough 15. Toprevent a return to the tank 6 of the liquid carried from the bath bythe strand 9, forwardly canted teeth are required, particularly on thegodet which first engages the strand. Such teeth abstract and lead theliquid from the strand into the pockets formed between the teeth,particularly during their upward movement. As the godet rotates andcarries the loaded pockets past their uppermost position, centrifugaland gravitation forces act on the liquid within the pockets causing thesame to discharge therefrom in. approximately a radial direction.

While it is essential in the method illustrated in Fig. 1 that the godetit! be provided with teeth that are canted forwardly in the direction ofrotation, the godet 12 may comprise a toothed section which is fluted,as shown in Fig. 2. The godets it and 12 have toothed sections forhandling the strand while in a highly plastic condition since, for a fewseconds after extrusion, the yarn is so tender that it is inadvisable tosubject it to much tension. Wet yarn will tend to wrap on a smooth godetsurface if it is not under a substantial tension and consequently flutedsurfaces are provided in handling yarns at low tension. While passingover the fluted surfaces, the coagulation and regeneration of the yarnproceeds to such an extent that the yarn may be thereafter subjected totension, such as applied during the stretching thereof. In the apparatusarrangements shown in Figs. 1 to 4, the yarn passes from the godets to atake-up system which-imparts sufficient tension to the yarn toaccomplish a desired amount of stretching. It is desirable to stretchthe yarn when it is positioned on the smooth godet surfaces since thestretching action is more uniformly applied than it would if the yarnwere on the non-continuous periphery of a godet section comprisingflutes or teeth. Furthermore, employment of smooth godet sections avoidsthe possibility f imposing impressions in the yarn, which may result ift. e yarn is stretched over the edges of the godet teeth. Suchimpressions tend to substantially reduce the denier of the yarn at thepoint of contact with the teeth and thus weaken the yarn, particularlyas the yarn tends to stretch more at the sections of reduced denier. Asillustrated, the maximum diameter of a fluted section of either of thegodets 10 and i2, and the other godets shown in the drawing that haveboth-fluted and smooth sections, is approximately the sameas that of itssmooth section.

The yarn passes from the hood 14 substantially free from coagulatingliquid in view of the centrifugal action imposed there-on by the godets,and then passes through the trough 15 toward a pair ofcanted take-uprolls 19 and 20. These rolls serve to store a take-up length of yarn forliquid treatments while passing over the rolls and engage theyarn withsufficient friction to enable stretching thereof over the portion of itspath extending between the points of contact with the godet 1t) and theroll 19. As the yarn passes from the godet 10, regeneration thereof hasprogressed to a stage that the yarn has sufi'icient tensile strength andthe plasticity is sufiiciently reduced to warrant stretching. However,to accelerate and continue the regeneration of the material comprisingthe filaments "of the yarn, the yarn is passed through the trough 15,into whici a heated liquid is introduced through a tube 21. The liquidflows countercurrently with respect to the movement of the strand and isdischarged into a receiver 22. The liquid used to promote regenerationmaybe simply hot water, or a very dilute acid solution. If the latter isused, the acid solution'applied to the rolls 19 and 20 may be recovered,heated, and pumped through the duct 21 to the trough. In addition toaccelerating the regeneration of the cellulose material of the yarn, thehot liquid in the trough 15 also plasticizes the green yarn thusfacilitating the stretching and improving the manner of its application.Solution for promoting the regeneration of the material comprising thestrand 9 may be supplementarily applied to a moreadvanced portion of thestrand, i. e., that portion wound about the rolls 19 and 20. Preferably,these rolls are inclined, as well as canted with respect to each other,so that the windings travel from the lower ends of the rolls lengthwisethereof to the upper ends, and liquid applied to the rolls will thenflow counter-currently to the movement of the strand while traversingthe rolls. It is desirable to further the regeneration of the strandwhile traversing these rolls, and to accomplish this, heated liquid,such as that fed into the trough 15, is applied to the rolls by a duct23 supported above the roll 19. The duct is disposed over a portion ofroll 19, not far from the strand discharging end of the roll.

If desired, a sizing solution may be applied to the .final wraps of thestrand through a duct 24, before passing the strand to a pair of dryingdrums 26 and 27. A stripper 28 may be mounted adjacent to the rolls 19and 20 to engage one or more windings passing from one roll to the otherto remove liquid from the strand before it reaches the portion of theroll 19 onto which the sizing solution is being applied from the duct24. The speed of the drums 26 and 27 may be. regulated to obtain anydesired magnitude of stretching or tension in the section of the strandpassingbetween the draft rolls l9 and 20 and the drying drums 26 and 27.After being dried, the strand passes to a packaging device representedby a traverse guide 29 and the spindle 30. Figs. 3 and 4 illustrateapparatus which may be substituted for a portion of the apparatusillustrated in Fig. 1 to provide a slightly modified method. Accordingto the arrangement shown in Fig. 3, fine streamsof filament formingmaterial, areextruded from a spinneret 36 into a tube 37. A filamentsetting liquid, such as a coagulant is forced through the tubeconcurrently with respect to the direction of passage of the strand froma housing 39 which surrounds the spinneret. A coagulant or other liquid,is supplied to the housing through a duct 40. The resulting strand andthe liquid are discharged into a container 42 which serves as'acollector for the liquid separated from the strand as it passes over apair of stripping devices'43 and 44. 'The strand, ,with the coagulantsubstantially removed therefrom, passes onto a fluted section 46 of thegodet 47. A godet 50, which may be connected in drive relationship withthe godet 47 by means, such as the worm' drive system 48, is supportedbelow the 'godet 47 and with its axis canted thereto. At least the godet50 is inclined downwardly so that its smooth section '51 rotates withina bath 52 of heated regenerating solution maintained' atf the' desiredlevel by an overflow means, such as a drainpipe 53. Additionalapplication of the regeneratingisoluti'on is "implemented by showerdevices 54 and 5, positionedover the smooth sections of godets 50 and 47respectively. The devices 54 and 55, as well as an inlet tube 57 for thecontainer 58, may be connected, as shown, t a system for supplying aregenerating solution comprising a pump 60 and a heat exchanger 61.Conventional automatic means (not shown) may be provided to control theoperation of the heat exchanger to provide heated solution to the showerdevices and the container 58 at an approximately constant temperature.

As shown in Figs. 3 and 4, the strand first travels over the flutedsections of the godets 47 and 50, then onto the smooth sections, andthen passes onto a pair of inclined rolls 64 and 65 having their axescanted relative to each other. The rolls 64 and 65 are driven at a speedsuch as to stretch the strand to a desired degree as it passes from thegodet 47 to the roll 64. Liquid treatments may be applied therebetweenand/or to the windings of the strand on the rolls 64 and 65, and furthertreatments, such as drying and packaging of the strand, may be carriedout in a manner as described with respect to the structure shown in Fig.l. The regenerating solution may consist of wash water collected fromthe rolls 64 and 65 in a container 66, and conducted to the exchanger 61through a tube 67.

Fig. illustrates a godet 74, similar to the godet described with respectto Fig. 'l, sectioned through its axis to expose the contour of theteeth 73. Material extruded from a spinneret 69 emerges from the bath 70as a bulky bundle of filamentary material constituting the strand 71.The bulk'iness of the strand is due to the low stage of coagulation andregeneration to which the filamentary material has advanced and also tothe considerable quantity of liquid carried from the bath whichsurrounds the filaments. The filaments at this stage are skinlikecasings of coagulated material enclosing liquid to plastic uncoagulatedand unregenerated material. The windings of the strand 71 which extendaround the godet 74 extend also around a guide 72 which may be employedin the manner of guides 80 and 84 of Figs. 6 and 7, respectively, toadvance the strand lengthwise of the axis of the godet '74. As thestrand 71 contacts the forwardly inclined teeth 73 of the godet 74, theliquid coagulant carried by the strand is pressed or forced from thestrand and collected within the pockets 75 formed along the forwardfaces of the teeth. Fig. 5 is drawn to accurately reproduce the effectof the godet upon the strand 7 1 and the liquid carried thereon asrevealed by photographs of actual operation. The liquid, as shown, iscarried by the forwardly inclined teeth of the godet around to approxiinately the point at which the teeth start downward in their revolutionabout the axis of the godet. As the teeth travel downward, the liquidcntained in the pockets 75 is discharged under the influence ofcentrifugal force and the progressively increasing affect ofgravitational force. As the teeth reach the lowest portion of theirrevolution, the liquid, collected within the pockets 75, is completelydischarged.

Fig. 6 illustrates a godet 78 having teeth, similar in cross sectionalcontour to the teeth 73 of Fig. 5, which extend almost entirelylengthwise of the godet and constitute the entire peripheralstrand-supporting section. A strand 79 is advanced longitudinallythereof by a guide 80. Fig. 7 illustrates a godet 81 having an annularsection 82, which is fluted to form 'teeth such as shown in Fig. 5, anda smooth section 83 which may be employed to snub the strand whendischarged toward a take-up device. A multi-finger guide 84 is used totraverse the strand lengthwise of the godet.

Fig. 8 illustrates apparatus that may be readily sub stituted for rolls19 and 20 of Fig. l, or rolls 64 and 65 of Fig. 3, and ancillaryequipment for carrying out liquid treatments. The apparatus of Fig. 8comprises a conventional thread-advancing reel 90 having sets ofinterdigitating strand-supporting bars 91 and 92. The reel is driven bya motor 94 and enclosed within compartments 95 and 96. Barfles 97 and 98separate the compartments to more eifectively carry out the separateapplications of liquid treatment, such as sprayingsepar'ate portions ofthe reel with a regenerating solution and a sizing solution. Forexample, the section of reel within the compartment may be sprayed by ashower device 99 while a small stream of sizing solution is administeredthrough a shower device 100 within the compartment 96. A winding of thestrand may be caused to pass over a stripping element 102 to removeregenerating solution from the strand before it passes into thecompartment 96. The compartments are provided with drainage ducts 104and 105 for disposal or recirculation of the solutions collected inrespective compartments. The reel is inclined, with its lowerend-portion disposed within the compartment 95, receiving the strand. Bysuch inclination, the liquid applied to the rolls moves countercurrentlywith respect to the reel and the strand passing thereover.

The invention is broadly concerned with the method of spinning yarns bya wet-spinning process wherein the coagulating or hardening fluid may beprevented from substantially mixing with the liquid applied in asucceeding treatment. The different liquids are effectively preventedfrom mixing by use ot'the godet systems hereinabove described comprisinggodets having fluted and smooth surfaces. Through the arrangement andoperation of such systems in accordance with the methods of theinvention, rapid conversion of a filament-forming material to a multiplefilament strand having a desired chemical state is accomplished, withmore efiicient use of spinning bath ingredients than possible withconventional apparatus. Moreover, the concentration and temperature ofthe spinning bath and other treating liquids actually in contact withthe yarn are subject to precise control whereby the quality of the yarnmay be controlled to a highly uniform level. A very important factor inthe control of the concentration of the spinning bath through which theextruded filament-forming material is drawn, is the continuous andautomatic liquid separation from the yarn, and the reuse of this dilutedspinning bath solution which contains water produced by coagulation ofthe aqueous filament-forming material. The application of the spinningbath liquid or coagulant may be controlled to obtain a high degree ofutilization of the ingredients which are discharged during the processand carry a relatively high concentration of by-products which may bereclaimed all the more economically.

While preferred embodiments of the invention have been shown anddescribed, it is to be understood that changes and variations may bemade without departing from the spirit and scope of the invention asdefined in the appended claims.

I claim:

The method of spinning a filamentary strand including the steps ofextruding a continuous running strand into a liquid bath, drawing thestrand upwardly through and out of said bath, passing the strand througha helical path about a rotatable godet having a serrated surface formedof circumferentially spaced teeth, said teeth each having a leadingsurface canted in the direction of the godet rotation to provide liquidreceiving pockets between said teeth, advancing the strand through itshelical path at approximately the same linear velocity as the portion ofthe strand drawn from said bath, collecting within said liquid receivingpockets substantially all of the liquid carried by those portions of thestrand moving in an upward direction as the strand moves through itshelical path to prevent said liquid from flowing along said strand in adirection opposite to its movement, discharging in a combined radial andtangential direction by the centrifugal and gravitational forcesdeveloped by said rotatable godet substantially all of the collectedliquid onto only those portions of the strand moving in a downwarddirection as the strand is passed through its helical path, and drawingthe strand from said godet at a linear yelocity greater thanthat portionof the strand drawn from said bath to place the same in tension.

References Cited in the file of this patent McLeIlan Sept. 18, 1945UNITED STATES PATENTS 6 Proctor Aug. 17, 1880 Dixon July 13, 1909Minahan Mar. 8,.1910 Johnson Mar. 23, 1926 Knebusch Aug. 31, 1937 10Blount Dec. 5, 1939 Uytenbogaart Sept. 2, 1941 Moritz Apr. 18, 1944Polak May 9, 1944 15

